Characterization of the crystalline regions of cured urea formaldehyde resin

Abstract

Urea formaldehyde (UF) resins are widely used thermosetting polymers in adhesives, finishes, molded objects, etc.

Hydrolytic, thermal, and UV stability of urea‐formaldehyde resin/thermally activated montmorillonite nanocomposites

“…The peaks at 2 θ values of 20.9, 21.9, and 24.3 are typical in the XRD spectrum for UF resin, which is in agreement with the studies of Liu et al 27 …”

“…Absorptions about 1239 cm −1 for CN and NH stretching vibration of tertiary amines, 1384 cm −1 for CH 2 OH, 1436 cm −1 for CH 2 stretching vibration, 1547 cm −1 for NH stretching vibration, 1630 cm −1 for NHCO stretching vibration, 2956 cm −1 CH 2 stretching vibration, and 3310 cm −1 for NH stretching vibration are observed for UF/ΔTK10 nanocomposites before and after UV irradiations. The other observed peaks about of 1130 cm −1 and 1035 cm −1 were assigned to CO aliphatic ether and methylene bridge (NCH 2 N), respectively 27 …”

“…The other observed peaks about of 1130 cm −1 and 1035 cm −1 were assigned to CO aliphatic ether and methylene bridge (NCH 2 N), respectively. 27 After UV radiation (λ = 254 nm), the intensities of all the peaks decreased for modified UF/ΔTK10 nanocomposite, with the increasing wavelength of light on the λ = 366 nm (Figure 4). Figure 4 shows that the intensity of the carboxyl group at 1630 cm −1 decreases with UV irradiation in modified UF/ΔTK10 nanocomposite.…”

Improved volatile cargo retention and mechanical properties of capsules via sediment-free in situ polymerization with cross-linked poly(vinyl alcohol) as an emulsifier

“…We repeated XRD with 3 different batches and this small peak consistently appeared on all diffractograms. Prominent peaks around 31L and 40L have been reported for more crystalline PUF at lower formaldehyde/urea (F/U) molar ratios < 1.4 [28,29]. The crystallinity for such PUF resin was calculated to be 26% at a F/U molar ratio of 1.6 and shown to decrease with increasing F/U molar ratio [30].…”

Preliminary Study on the Physical and Mechanical Properties of Poplar Wood Modified by Waterborne Glucose Silicone Resin

“…1(a) (b) is the infrared spectrum of the resin. 3600-3100 cm -1 is the coupling vibration peak of -NH and -OH [14]; the absorption peaks of 2926cm -1 , 2937 cm -1 , and 2885cm -1 are attributed to the stretching vibration of -CH2- [15][16], 1667cm -1 is the stretching vibration peak of the urea amide carbonyl group; 1630cm -1 is the characteristic peak of amide absorption band II, reflecting the in-plane bending vibration of the N-H bond of urea CO-NH2 [17]; 1552cm -1 is the coupling of the in-plane bending vibration of the N-H bond in CO-NH-and the stretching vibration of the C-N bond [17][18]; 1421cm -1 is the CH bending vibration in -N-CH2-and -CH2-O- [18]; 1120cm -1 . The absorption peak at 1029cm -1 is attributed to the asymmetric stretching vibration of -C-O [16].…”